Why Has Linux RMAN Script Stopped Working With My Oracle Backup?

I'm running Linux 5.7, Oracle 11.2.0.3, and Rman. I use Netbackup to back up my infrastructure. NB calls my RMAN script where the Rman commands are issued, launches the tape backups, and writes out an audit trail. This process has worked for months, but all of a sudden, the backup stopped running, and obviously the output log stopped being produced. I can't think of a thing that I may have done to cause this to happen. Through lots of debugging, I have determined that the { character in the script that surrounds the code where the audit trail is produced is an issue. If I remove the { character, the backup runs, but I don't get the audit trail. Also, I have another server running identical OS, database, etc. that still works fine. I even copied the working script from this server and used it, but it doesn't work either. What could have caused brackets to stop working??

Since ...You have not made changes..
I would reboot the netbackup server and use a copy of the same script
by backing up only a single tablespace as a test case and doing this may
help you because
generally a production script would run only at night
and hence you could spend a few days trouble shooting
this.

#
# Replace ${ORACLE_HOME}/scripts, below, with the NetBackup Oracle script
# path. Since subsequent installs or deinstalls will remove this file,
# you will want to move this script from its installed location before
# making updates.
#

#
# Call Recovery Manager to initiate the backup. This example does not use a
# Recovery Catalog. If you chose to use one, remove the option, nocatalog,
# from the rman command line below and add a 'connect rcvcat' statement to
# the corresponding command file ($CMDFILE). An alternative to putting the
# connect statements in the command file would be to add them to the rman
# command line.
#
# Note: Any environment variables needed at run time by RMAN or $CMDFILE
# must be set and exported within the switch user (su) command.
#

echo
echo This script has been modified from its original version
echo
echo $CMDFILE